. The structure and classification of birds . asseres the truncation is in front ofthis line. The swifts are intermediate,the truncation being, as is shown inthe accompanying figure (fig. 104),about on a level with the line joiningthe inaxillo-palatines. It is true thatthe lateral processes so characteristicof the segithognathous skull are betterdeveloped in the swifts than in theswallows ; but, on the other hand, itmust be borne in mind that the un-doubtedly segithognathous Indicatoris without these processes. In bothswifts and humming birds the skull isholorhinal and without basipterygoidpro
. The structure and classification of birds . asseres the truncation is in front ofthis line. The swifts are intermediate,the truncation being, as is shown inthe accompanying figure (fig. 104),about on a level with the line joiningthe inaxillo-palatines. It is true thatthe lateral processes so characteristicof the segithognathous skull are betterdeveloped in the swifts than in theswallows ; but, on the other hand, itmust be borne in mind that the un-doubtedly segithognathous Indicatoris without these processes. In bothswifts and humming birds the skull isholorhinal and without basipterygoidprocesses. As to the vomer, HuxLBT described it as truncated ;but Shufeldt finds it to end in an .excessivdy fine point. In swifts the vomer is, as alreadystated, truncated. But as to this difference and its value asa means of separating the birds cf. the manifold vomer ofLimicolae. The humming birds have fourteen or fifteen {TrochilusAlexandri) cervical vertebra. The Cypselidas have thirteenor fourteen. Four ribs^ join the sternum on each side. Fig, 304.—Skull op Micro-pus melanoleucw. (Aftek Shufeldt.) Ptux, premaxilla; May>, masdllo-palatlnes; Vo, vomer; iVa,nasal; PI, palatine ; Pt, ptery-goid. glda, and Cypselidse, P. Z. S. 1885, p. 886, and 1886, p. 501. See also Zbhntner, Beitrage z. Entwioklung von Cypselus melba, Arch. f. Naiurg. Ivi. 1890, p. 189 (transl. in Ibis, 1890, p. 196). Loc. cit. (on p. 196.) Fcrbeingek says five or six. 230 STRUCTURE AND CLASSIFICATION OF BIRDS in both groups of birds. The sternum in both is unnotchedand broader behind than in front. In the fore hmb the length of the hand distinguishes
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